See What Sinks and Floats
You’ll need a large container or bucket full of water. Go on a nature walk and collect items such as rocks, pumice, pine cones, feathers, leaves, seeds, nuts etc. As you collect things, discuss with the children whether they think they’ll float or sink and why.
When you have finished collecting objects, get the children to predict which items will float and which ones will sink. They can sort them into 2 piles. The discussion around the decision is important, so let them debate with each other. After predictions have been made, check them! Put each object in the water to test the predictions. Discuss any that they predicted incorrectly. This can be a really great time to introduce the concept of density. “Why did the big bit of pumice float, but the smaller rock sink? Because the smaller rock was denser than the pumice, which is full of air bubbles.”
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